Question

解几道较简单的二元一次方程组（1）x/3-y/15=4/3 (2)0.5x+0.8y=4.7 x/4-y/10=4/3

Answer 1

（1）5x-y=20 ----------a

5x-2y=80/3--------b

a-b:y=-20/3

x=8/3

(2) 1.5x+2.4y=14.1 -----------a

1.2x+2.4y=13.2 -----------b

a-b:0.3x=0.9

x=3

y=4

(3）3x-2y=(x-3y)/5

2x=y

所以,3x-2y=（2x-1)/4

3x-4x=（2x-1)/4

-4x =2x-1

x =1/6

y=1/3